Exploring Preliminary Results of Ibrutinib and Fludarabine in CLL

Christopher Pleyer, MD, a staff clinician at the National Heart, Lung, and Blood Institute, discusses the phase 2 study of ibrutinib (Imbruvica) and short-course fludarabine in previously untreated patients with chronic lymphocytic leukemia (CLL).

There is 2-year follow-up data available for this study, although the investigators are still waiting for longer-term results. After these 2 years, the primary efficacy analysis showed that 40% of patient achieved complete remission (CR) with the combination. Notably, this rate was slightly higher than what is typically seen with ibrutinib as a single agent, according to Pleyer; the CR rates with ibrutinib monotherapy are usually somewhere between 15% and 20%. Pleyer says because this was not a randomized trial, it is difficult to compare it to other trials, but these preliminary results demonstrated encouraging CR rates for patients with CLL.

The combination was well tolerated in this study, and no additional toxicities were found. Pleyer explains that specifically with fludarabine, there was worry about long-term depletion of T cells, but this was not shown in the study. They also did not observe a significant increase in the number of infections.